Impeller for flotation machines



Feb. 12 1924, 1,483,115

C. E. RORK ET AL.

IMPELLEB FOR FLOTATION MACHINES I 0rigina1.Filed June 13, 917 2 Sheets-Sheet 1 INVENTORS C. E. PORK A. SAND/BERG BY ATTORNEYS Feb; 12 1924 1,483,115

' v c. E. RORK ETAL IMPELLER'FOR FLOTATION MACHINES Original Filed June 13 ,1917 2 Sheets-Sheet 3 Q1 v A TTORNEKS Patented Feb. 12, 1924.

' uu'rso STATES PATENT OFFICE. v

CHARLES E. ROBK,OF DOUGLAS, ARIZONA, AND AUGUST SANDBERG, OF NEW YORK, N. Y., ASSIGNORS TO WILLIAM A. BUTCHART, OF DENVER, COLORADO.

IMPELLER FOR FLO TATION MACHINES.

Original application filed June 13, 1917, Serial No, 174,583. Divided and this application filed December 29, 1920. Serial No. 433,867.

T c all whom it may concern:

Be it known that we, CHARLES E. Born, a citizen of the United States. and AUGUST SANDBERG, a subject of the King of Sweden,

6 residing, respectively, at Douglas, Arizona, and New York, N. Y., have invented a cor tain new and useful Improvement in Impellers for Flotation Machines, of which the following is a full, clear, and exact descrip- 10 tion, such as will enable others skilled in the art to which it appertains to make and use the same.

This application is a division of our pending application for patent on flotation machirzies, Serial No. 174,583, filed June 13,

The invention relates to anagitator or impeller capable of use for various purposes, but particularly designed for use in a flotation machine.

The main object of the invention, is to provide an agitator or impeller which is so constructed that itwill not only serve as a mechanical agitator, but'also as a means for 85 beating, whipping or blowing air or any other suitable gas into or through a liquid or mixture of liquids which it is desired to aerate.

Another object is to provide an agitator or impeller for flotation machines that will initially aerate the pulp in the agitating chamber of the machine in a novel manner, and thereafter discharge said aerated pulp into the settling chamber of the machine.

And still another object is to provide a strong and serviceable impeller for flotation machines that is inexpensive to construct and install. Other objects and desirable features of our invention will be hereinafter pointed out.

Figure 1 of the drawings is a transverse sectional view of a flotation machine equipped with an impeller constructed In accordance with our invention.

Figure 2 is a vertical longitudinal sectional view of said machine, showing the im eller in elevation; and

igure 3 is a longitudinal sectional view of said machine, showing the impeller in 00 vertical section.

Referring to the drawings which illustrate the preferred form of our invention, A

designates the agitating chamber of a flotation machine that is adapted to receive pulp,

and B designates a settling chamber arranged at one side of said agitating chamber and separated from same by a vertically-disposed partition 1. A rotatable agitator or impeller C that is arranged in the ag tat ng chamber A causes the pulp in said agitating chamber to be aerated and thereafter discharged laterally over the upper edge of said partition 1' into the settling chamber B, the settling chamber being connected with the agitating chamber by discharge passageways 2 that lead from the lower portion of said settling chamber to the lower portion of the agitating chamber,

as shown in Figure 1. The agitator or impeller C consists of a horizontally'disposed shaft 48 arranged longitudinally of the agitating chamber and journaled in bearings 47 located at the ends of said chamber, a

plurality of spiders 58, preferably formed of metal, arranged in spaced relation on said shaft 48' and securely connected to same by keys 57, and impeller blades 61, preferably formed of wood andlarranged longitudinally of the shaft 48 in notches or seats formed in the circular rims or peripheral portion of the spiders 58 and secured to said spiders by removable locking keys 62 that are arranged in co-operating grooves in the blades and in the notches in the circular rims of the spi' 'ders in which the blades are seated. As shown in Figure 1, the blades 61 are spaced a art and extend from the spiders 58 at a s ight angle to the radial so that they form in effect shallow lifting buckets which scoo up the material from the bottom of the agitating chamber and move said material upwardly to permitdischarge of same over the upper edge of the partition 1 into the settling chamber.

Collars 50 which are secured to the shaft 48 of the impeller prevent said shaft from moving longitudinally, and the end walls of the agitating chamber through which the shaft 48 asses are provided with openings that are c osed by plate-like castings 52 having openings 54 through which the shaft 48 passes. The shaft openings v54 in the castings 52 are surrounded by splash guard flanges 55 that co-operate with drip collars 56 on the shaft 48 to prevent liquid from splashing out of the agitating chamber through the openings 54 when the impeller is in operation,

The agitating chamber A is provided with a false bottom 86 of substantially arcuate shape in cross section that corresponds approximately in curvature to the curvature of the peripher or outer portion of the impeller and w ich extends downwardly from the intermediate portion of the 'front wall of the agitating chamber to a point slightly beyond a vertical plane passing through the shaft48 of the impeller, as shown in Figure 1. A longitudinally-disposed bafile block 90, preferably of substantially triangular shape in cross section, is arranged between the impeller C and the outlet passageways 2 leading from the settling chamber, and a longitudinally-disposed bafile block 91 of similar shape in cross section is arranged in the upper portion of the agitating chamber at a point above the propeller, as shown in Figure 1, said baflle block 91 bein provided with a covering of rubber belting 93 or other suitable material so as to prevent the mineral matter being treated from adboring to said baille block.

At one end of the an inlet chamber 97 provided with a discharge opening 99 that leads into the agitating chamber, as shown in Figure 2, the pulp that is to be treated beingsupplied to the chamber 97 through a supply pipe 101. At the opposite end of the machine a discharge pipe 102 communicates with the lower portion of a discharge chamber at the right hand end of the agitating chamber, said dischar e pipe 102 being connected by means oi an elbow 103 to a stand pipe 10-1 whose upper end is connected by means of a T coupling 105 and an elbow 106 to a depending outlet pipe 107. By this means the gangue discharged from the machine is drawn from the lower portion of the discharge chamber at the right hand end of the agitating chamber and at the same time a suitable liquid level maintained in the agitating chamber, due to the fact that the discharge piping has a vertically-disposed return bend which prevents the liquid from being exhausted from the machine to a level below that of the T coupling 105.

hen the machine is in operation pulp is fedat the proper rate through the pipe 101 into the inlet end of the agitating chamher in which the impeller C is being rotated at a high speed in the direction indicated by the arrow in Figure 1. If the impeller operates at a working speed of approximately 200 R. P. M., the pulp or liquid in the machine will be kept at a working level near the upper edge of partition 1 between the agitating and settling chambers, due to centrifugal action. In other words, the rotary movement of the impeller causes all liquid within the space occupied by the impeller to be forced out by centrifugal action, the high speed of theimpeller causagitating chamber is means ing the liquid which enters the space between the impeller and the partition 1 to be carried upwardly and converted into a spray in the upper portion of the agitating chamber adjacent the upper edge of the partition 1.

As above stated, the rapidly revolving blades at the lowerand middle portions of the impeller lift the pulp at considerable velocity through the space between the impeller and partition 1. and when centrifugal force causes the pulp to be thrown oil the blades of the propeller at a point in proximity to the upper edge of the partition 1, said pulp is broken into fine streams, drops and spray. The impeller further acts as a suction fan and blower, drawing air into the agitating chamber through openings 54 and blowing or forcing it into and through the pulp while the latter is in suspension in the space above the liquid level, bounded by the baffle 91, cover 22 and vertically-disposed wall 73 (see Figure 1). The pulp is thereby thoroughly agitated and aerated before it leaves the agitating chamber, with the consequent production of a large volume of mineral carrying bubbles essential to the recovery of values by froth flotation. The pulp with the entrained air and bubbles is discharged over the upper edge of the partition 1 through the space between that partition and the wall 73 into the settling chamber in a direction opposite to that of the rotation of the impeller. The froth rises to the surface in the settling chamber, passes over the top of partition and with its attached mineral is discharged from the machine. The pulp returns through the passageways 2 to the agitating chamber for further treatment and is finally discharged from the machine through outlet pipe 107.

in view of the fact that the discharge opening of the agitating chamber, formed by the space between the upper edge of the partition 1 and the ballie block 91, is located at a point below the upper side of the impeller C, the pulp will be discharged from the agitating chamber without being car'- ried over the top side of the impeller. In other words, the impeller C only has to lift the pulp a relatively slight distance, and accordingly, the power consumption of our machine is materially less than a machine of the type in which the impeller is 'so designed that the pulp is carried upwardly over the top side of the impeller and dis charged from the agitating chamber at a point above or in proximity to the top side of the impeller. The baflle block 91 prevents the pulp}: from being carried completely arounda'the agitating chamber by the impeller and the bafie" block 90 prevents back pressure from being created in the discharge passageways 2 leading from the the end settling chan'lber, due to the rotary movement of the impeller.

Having thus described our invention, what we claim as new and desire to secure by Letters Patent, is:

A combined aerating device and pulp agitutor for floatation machines, comprising a horizontally-disposed, rotatable shaft, rigid spiders on said shaft arranged in spaced relation and each provided with a circular rini portion, a plurality of blades arranged parallel to said shaft and set edgewise in the rim portions of said spiders with their,

outer edge portions pointingaafoliwardly and proj ecting beyondr thei" rims-portions of the spiders,- andremoiable keys for detachably connecting said blades to said spiders arranged longitudinally of said blades in cooperating key-ways formed in the blades and in the circnlanrim portions of the 20 spiders.

CHARLES E. ROB-K. AUGUST SANDBERG. 

